/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.hddz.comlib.ui.base.quicksearchbox;

import android.os.SystemClock;

/**
 * Tracks latency in wall-clock time. Since {@link #getLatency} returns an
 * {@code int}, latencies over 2^31 ms (~ 25 days) cannot be measured. This
 * class uses {@link SystemClock#uptimeMillis} which does not advance during
 * deep sleep.
 */
public class LatencyTracker
{
	/**
	 * Start time, in milliseconds as returned by
	 * {@link SystemClock#uptimeMillis}.
	 */
	private long	mStartTime;

	/**
	 * Creates a new latency tracker and sets the start time.
	 */
	public LatencyTracker()
	{
		mStartTime = SystemClock.uptimeMillis();		//返回起始时间
	}

	/**
	 * Resets the start time.
	 */
	public void reset()
	{
		mStartTime = SystemClock.uptimeMillis();		//重新设置起始时间
	}

	/**
	 * Gets the number of milliseconds since the object was created, or
	 * {@link #reset} was called.
	 */
	public int getLatency()
	{
		long now = SystemClock.uptimeMillis();		
		return (int) (now - mStartTime);				//返回运行时间
	}
}
